This condition is an abnormal relationship between the muscles that mobilize and the muscles that stabilize the joint. Normally these muscles work together to move and stabilize the arm. When these muscles become imbalanced, the mobilizing muscles begin to overpower the weaker stabilizing muscles. This can interfere with normal movement of the shoulder, causing instability.
This condition can be caused by repetitive motions that work the muscles unevenly. It can also be caused by injury to the shoulder.
Symptoms can include weakness, fatigue, and loss of range of motion in the shoulder.
Muscle imbalance is treated with physical therapy.